Introduction to Computer Networks CMPE 150 Fall 2005 Lecture 1 CMPE 150 Introduction to Computer Networks 1 Class Information Class time and location M W F from 2 00 3 10 E2 180 Class Web page http www cse ucsc edu classes cmpe150 Fall05 Instructor Katia Obraczka E2 323 Office hours TBD katia soe ucsc edu CMPE 150 Introduction to Computer Networks 2 Class Information Teaching Assistant Sudharsan Rangarajan E mail sudrang soe ucsc edu Lab Assistants Jay Boice boice soe ucsc edu Todd Nagengast todd soe ucsc edu CMPE 150 Introduction to Computer Networks 3 Textbook CMPE 150 Introduction to Computer Networks 4 Pre requisites CMPE 16 CMPE 12C L CMPE 150 Introduction to Computer Networks 5 Focus Intro to data networks from an engineering perspective Broad coverage Network architectures Network protocols Layered design Protocol stack TCP IP and the Internet Hands on aspect CMPE 150 Introduction to Computer Networks 6 Topics Covered Introduction and Overview Physical Layer Medium Access Control MAC Link Layer Network Layer Routing CMPE 150 Introduction to Computer Networks Internetworking and IP IP Routing and Control Transport Layer Application Layer Putting It All Together 7 Other Networking Courses CE 151 CE 152 CE 156 CE 107 EE 103 CE 154 CE 153 EE 151 CE 108 CE 163 CS 111 Network Administration Protocols Network Programming Stochastic System Analysis Signals and Systems Data Communication Digital Signal Processing Communications Systems Data Compression Multimedia Operating Systems CMPE 150 Introduction to Computer Networks 8 Grading Mid term Assignments 35 25 Homework Labs Final 40 No credit for work that is not your own CMPE 150 Introduction to Computer Networks 9 Academic Integrity Academic integrity policies will be strictly enforced Academic integrity policy violations will NOT be tolerated http www ucsc edu academics academic integrity policy html CMPE 150 Introduction to Computer Networks 10 Course Outline Introduction History basic concepts terminology More not so basic concepts protocols layering etc Physical layer Transmitting data Data link layer Reliable transmission Accessing the communication medium Medium access control protocols LANs Ethernet token ring wireless LANs CMPE 150 Introduction to Computer Networks 11 Course Outline cont d Network layer Types of network services Circuit vs packet switching Virtual circuits and datagrams Routing Addressing Unicast and multicast Internetworking IP The Internet IP Routing and Control CMPE 150 Introduction to Computer Networks 12 Course Outline cont d Transport layer E2E communication Types of transport service Connectionless versus connection oriented UDP TCP Application layer DNS ssh telnet ftp news e mail The Web HTTP HTML Search engines Proxy and caches Peer to peer Security CMPE 150 Introduction to Computer Networks 13 What s a network CMPE 150 Introduction to Computer Networks 14 What s a network Merriam Webster Dictionary A fabric or structure of cords or wires that cross at regular intervals A system of computers terminals and databases connected by communication lines A computer network is defined as the interconnection of 2 or more independent computers Ramteke Networks pg 24 CMPE 150 Introduction to Computer Networks 15 Why network Before networks One large computer mainframe used for all processing in businesses universities etc Smaller cheaper computers Personal computers or workstations on desktops Interconnecting many smaller computers is advantageous Why CMPE 150 Introduction to Computer Networks 16 Ubiquitous Computing Computers everywhere Also means ubiquitous communication Users connected anywhere anytime PC laptop palmtop equivalent to cell phone Networking computers together is critical CMPE 150 Introduction to Computer Networks 17 Computer Network Provide access to local and remote resources Collection of interconnected end systems Computing devices mainframes workstations PCs palm tops Peripherals printers scanners terminals CMPE 150 Introduction to Computer Networks 18 Why network Resource sharing Hardware printers disks terminals etc Software text processors compilers etc Data Robustness Fault tolerance through redundancy Load balancing Processing and data can be distributed over the network Location independence Users can access their files etc from anywhere in the network CMPE 150 Introduction to Computer Networks 19 Problems Security It s much easier to protect centralized resources than when they are distributed Network itself as the target CMPE 150 Introduction to Computer Networks 20 Some History CMPE 150 Introduction to Computer Networks 21 Before the Internet Postal network Delivers different types of objects letters packages etc world wide Relatively high delay but relatively cheap Sender and receiver identified by their postal address name number street city etc Telephone network Engineered to deliver real time voice Also world wide Low delay but more expensive Users identified but telephone number CMPE 150 Introduction to Computer Networks 22 The Telephone Network CMPE 150 Introduction to Computer Networks 23 The Telephone Network Telephone was patented by G Bell in 1876 For one telephone to be able to talk with another telephone a direct connection between the two telephones was needed Within one year cities were covered with a wild jumble of wires CMPE 150 Introduction to Computer Networks 24 The Telephone Network cont d In 1878 the Bell Telephone company opened its first switching office in New Haven CT Each user would connect to the local switching office When a user wanted to make a call s he rang to the office and would be manually connected to the other end CMPE 150 Introduction to Computer Networks 25 The Telephone Network cont d To allow for long distance calls switching offices switches were connected Several connections can go through inter switch trunks simultaneously At some point there were too many connections between switching offices CMPE 150 Introduction to Computer Networks 26 The Telephone Network cont d Thus a second level hierarchy was added The current telephone system has at least five levels of hierarchy CMPE 150 Introduction to Computer Networks 27 Addressing Uniquely identifies users Examples Postal address telephone number Types of addresses Flat Hierarchical Are postal addresses flat or hierarchical And phone numbers CMPE 150 Introduction to Computer Networks 28 POTS or PSTN For over 100 years the POTS Plain Old Telephone System a k a PSTN Public Switched
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